Algebra II : Negative Exponents

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #3171 : Algebra Ii

Evaluate:

\displaystyle 24^{-2}

Possible Answers:

\displaystyle -\frac{1}{576}

\displaystyle -48

\displaystyle \frac{1}{576}

\displaystyle -576

\displaystyle -24

Correct answer:

\displaystyle \frac{1}{576}

Explanation:

When exponents are negative, we can express them using the following relationship:

\displaystyle x^{-a}=\frac{1}{x^a}.

In this format, \displaystyle x represents the base and \displaystyle a represents the exponent. A negative exponent becomes positive when it is rewritten as a reciprocal.

Therefore: 

\displaystyle 24^{-2}=\frac{1}{24^2}=\frac{1}{576}

Example Question #511 : Mathematical Relationships And Basic Graphs

Evaluate:

\displaystyle \left(\frac{1}{7}\right)^{-3}

Possible Answers:

\displaystyle \frac{1}{21}

\displaystyle -\frac{1}{343}

\displaystyle 343

\displaystyle -343

\displaystyle \frac{1}{343}

Correct answer:

\displaystyle 343

Explanation:

When exponents are negative, we can express them using the following relationship:

\displaystyle x^{-a}=\frac{1}{x^a}.

In this format, \displaystyle x represents the base and \displaystyle a represents the exponent. A negative exponent becomes positive when it is rewritten as a reciprocal.

Therefore: 

\displaystyle \left(\frac{1}{7}\right)^{-3}=\frac{1}{\frac{1}{7^3}}=\frac{1}{\frac{1}{343}}

Dividing by a fraction is the same as multiplying by its reciprocal. 

\displaystyle \frac{1}{\frac{1}{343}}=1 \times \frac{343}{1}= 343

Example Question #43 : Negative Exponents

Evaluate: 

\displaystyle \left(\frac{2}{3}\right)^{-4}

Possible Answers:

\displaystyle -\frac{16}{81}

\displaystyle -\frac{4}{9}

\displaystyle \frac{16}{81}

\displaystyle -\frac{81}{16}

\displaystyle \frac{81}{16}

Correct answer:

\displaystyle \frac{81}{16}

Explanation:

When exponents are negative, we can express them using the following relationship:

\displaystyle x^{-a}=\frac{1}{x^a}.

In this format, \displaystyle x represents the base and \displaystyle a represents the exponent. A negative exponent becomes positive when it is rewritten as a reciprocal.

Therefore: 

\displaystyle \left(\frac{2}{3}\right)^{-4}=\frac{1}{(\frac{2}{3})^3}=\frac{1}{\frac{16}{81}}

Dividing by a fraction is the same as multiplying by its reciprocal. 

\displaystyle \frac{1}{\frac{16}{81}}=1\times\frac{81}{16}=\frac{81}{16}

Example Question #512 : Mathematical Relationships And Basic Graphs

Simplify: \displaystyle 12^{-12}

Possible Answers:

\displaystyle \frac{1}{12^{-12}}

\displaystyle -\frac{1}{12^{12}}

\displaystyle -12^{12}

\displaystyle 12^{12}

\displaystyle \frac{1}{12^{12}}

Correct answer:

\displaystyle \frac{1}{12^{12}}

Explanation:

When dealing with negative exponents, we convert to fractions as such: \displaystyle x^{-a}=\frac{1}{x^a} which \displaystyle a is the positive exponent raising base \displaystyle x.

\displaystyle 12^{-12}=\frac{1}{12^{12}}

Example Question #41 : Exponents

Simplify: \displaystyle \frac{1}{64}^{-3}

Possible Answers:

\displaystyle 64

\displaystyle \frac{1}{262144}

\displaystyle -\frac{1}{262144}

\displaystyle 262144

\displaystyle -262144

Correct answer:

\displaystyle 262144

Explanation:

When dealing with negative exponents, we convert to fractions as such: \displaystyle x^{-a}=\frac{1}{x^a} which \displaystyle a is the positive exponent raising base \displaystyle x.

\displaystyle \frac{1}{64}^{-3}=\frac{1}{\frac{1}{64^3}}=\frac{1}{\frac{1}{262144}}=262144

Example Question #46 : Understanding Exponents

Evaluate: \displaystyle \frac{1}{64}^{-\frac{1}{3}}

Possible Answers:

\displaystyle \frac{1}{4}

\displaystyle -128

\displaystyle \frac{1}{262144}

\displaystyle -262144

\displaystyle 4

Correct answer:

\displaystyle 4

Explanation:

When dealing with fractional exponents, we rewrite as such: \displaystyle x^{\frac{a}{b}}=\sqrt[b]{x^a} which \displaystyle b is the index of the radical and \displaystyle a is the exponent raising base \displaystyle x. When dealing with negative exponents, we convert to fractions as such: \displaystyle x^{-a}=\frac{1}{x^a} which \displaystyle a is the positive exponent raising base \displaystyle x.

\displaystyle \frac{1}{64}^{-\frac{1}{3}}=\frac{1}{\frac{1}{\sqrt[3]{64}}}=\frac{1}{\frac{1}{4}}=4

Example Question #47 : Understanding Exponents

Evaluate: \displaystyle \frac{1}{8}^{-\frac{2}{3}}

Possible Answers:

\displaystyle \frac{1}{2}

\displaystyle 4

\displaystyle -\frac{1}{4}

\displaystyle -4

\displaystyle -\frac{1}{12}

Correct answer:

\displaystyle 4

Explanation:

When dealing with fractional exponents, we rewrite as such: \displaystyle x^{\frac{a}{b}}=\sqrt[b]{x^a} which \displaystyle b is the index of the radical and \displaystyle a is the exponent raising base \displaystyle x. When dealing with negative exponents, we convert to fractions as such: \displaystyle x^{-a}=\frac{1}{x^a} which \displaystyle a is the positive exponent raising base \displaystyle x.

\displaystyle \frac{1}{8}^{-\frac{2}{3}}=\frac{1}{\frac{1}{\sqrt[3]{8^2}}}=\frac{1}{\frac{1}{4}}=4

Example Question #48 : Understanding Exponents

Evaluate: \displaystyle 5^{-8}

Possible Answers:

\displaystyle -5^{-8}

\displaystyle -\frac{1}{5^8}

\displaystyle \frac{1}{5^{-8}}

\displaystyle \frac{1}{5^8}

\displaystyle -5^8

Correct answer:

\displaystyle \frac{1}{5^8}

Explanation:

When dealing with negative exponents, we convert to fractions as such: \displaystyle x^{-a}=\frac{1}{x^a} which \displaystyle a is the positive exponent raising base \displaystyle x.

\displaystyle 5^{-8}=\frac{1}{5^8}

Example Question #41 : Negative Exponents

Evaluate \displaystyle 21^{-2}

Possible Answers:

\displaystyle 441

\displaystyle -42

\displaystyle -441

\displaystyle \frac{1}{441}

\displaystyle -\frac{1}{441}

Correct answer:

\displaystyle \frac{1}{441}

Explanation:

When expressing negative exponents, we rewrite as such: 

\displaystyle x^{-a}=\frac{1}{x^a} 

in which \displaystyle a is the positive exponent raising base \displaystyle x.

\displaystyle 21^{-2}=\frac{1}{21^2}=\frac{1}{441}

Example Question #50 : Understanding Exponents

Evaluate \displaystyle -4^{-4}

Possible Answers:

\displaystyle \frac{1}{16}

\displaystyle -\frac{1}{256}

\displaystyle 16

\displaystyle \frac{1}{256}

\displaystyle -\frac{1}{16}

Correct answer:

\displaystyle -\frac{1}{256}

Explanation:

When expressing negative exponents, we rewrite as such: 

\displaystyle x^{-a}=\frac{1}{x^a} 

in which \displaystyle a is the positive exponent raising base \displaystyle x.

\displaystyle -4^{-4}=-\frac{1}{4^4}=-\frac{1}{256}

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